Troubled waters: Experts try to figure out flooding along 103rd Street
By Jill Draper
KC Water engineers and other experts are building a huge model of Indian Creek to figure out why the flood plain map doesn’t accurately predict which areas will flood during heavy downpours.
After a record-breaking flood along Indian Creek in July 2017, followed by an even higher flood a month later, some businesses stayed dry that should have been inundated—at least according to the current computer model.
“We were surprised, yes,” says Tom Kimes, the water department’s stormwater utility engineering manager. “But we had a theory.”
That theory will be tested in late spring when Kimes’ team turns on the tap to pump 300 gallons of water a minute across a foam model of the creek bed and surrounding area. The model stretches 70 by 25 feet atop a membrane-lined platform to mimic the land along 103rd Street from State Line Road to east of Wornall.
The test will take place downtown a few blocks from City Hall in a KC Water maintenance building where the $400,000 model is still under construction.
So what’s the theory? Kimes and others think floodwater is escaping the channel at some point along 103rd Street, in effect becoming two channels, then flowing back in and going out again at Wornall and nearby areas.
“Kansas City is really on the cutting edge with this technology,” says Kimes. “I think it’s going to tell us stuff that computers can’t. There really is no substitute for physical observation.”
The cost of the model is being split between the city and the Army Corps of Engineers. Data to build it was collected by aircraft equipped with LIDAR, remote sensing technology that measures land and riverbeds with laser pulses.
A company in Prairie Village, Water Resources Solutions, is working with the city and the corps
to convert the data into three-dimensional mapping files. Those files are then sent to the Metropolitan Community College’s fabrication lab, where a computer-controlled robotic cutter reads them and carves blocks of foam into corresponding land contours, which are pieced together like a giant puzzle to form a miniature landscape.
Other cities that use this technology are mostly large ports trying to understand tides, although Mission Hills in Kansas built a smaller scale flood model with the same method, Kimes says.
KCMO engineers have studied physical models in the past, especially to analyze flooding along Brush Creek in the Country Club Plaza area. That model was hand-built from concrete about 30 years ago by the Army Corps of Engineers in Vicksburg, Miss. Newer methods produce more accurate information.
“The question is what would a flood control project for Indian Creek look like?” Kimes says. “Our recommendation to City Council is not to build something comparable to Brush Creek’s widening and deepening, but to consider other options.”
Because the new model will be more sophisticated, he expects it will help KC Water take a targeted strategy “so that we can preserve the beauty of the whole Watts Mill area.” The department already has bought two houses on Washington Street and one on the creek’s north bank. More buy-outs might be considered in the future.
“Streams need more space than people often realize,” Kimes says. “People don’t always understand this when it’s not flooding and they just see dry land.”
In late summer or early fall the public will be invited to view the model and see a demonstration of the flood simulation. Also in the fall public meetings will be held at the Trailside Center to discuss the best use of the new green space created at 103rd Street and Wornall Road after Coach’s Bar & Grill and other businesses were torn down. According to Kimes, KC Water will maintain the space, which probably will include a trail and seating.